3HU6 image
Entry Detail
PDB ID:
3HU6
Title:
Structures of SPOP-Substrate Complexes: Insights into Molecular Architectures of BTB-Cul3 Ubiquitin Ligases: SPOPMATHx/BTB/3-box-PucSBC1
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2009-06-13
Release Date:
2009-10-20
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Free:
0.29
R-Value Work:
0.23
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Speckle-type POZ protein
Mutations:D140G
Chain IDs:A, B
Chain Length:312
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
Structures of SPOP-substrate complexes: insights into molecular architectures of BTB-Cul3 ubiquitin ligases.
Mol.Cell 36 39 50 (2009)
PMID: 19818708 DOI: 10.1016/j.molcel.2009.09.022

Abstact

In the largest E3 ligase subfamily, Cul3 binds a BTB domain, and an associated protein-interaction domain such as MATH recruits substrates for ubiquitination. Here, we present biochemical and structural analyses of the MATH-BTB protein, SPOP. We define a SPOP-binding consensus (SBC) and determine structures revealing recognition of SBCs from the phosphatase Puc, the transcriptional regulator Ci, and the chromatin component MacroH2A. We identify a dimeric SPOP-Cul3 assembly involving a conserved helical structure C-terminal of BTB domains, which we call "3-box" due to its facilitating Cul3 binding and its resemblance to F-/SOCS-boxes in other cullin-based E3s. Structural flexibility between the substrate-binding MATH and Cul3-binding BTB/3-box domains potentially allows a SPOP dimer to engage multiple SBCs found within a single substrate, such as Puc. These studies provide a molecular understanding of how MATH-BTB proteins recruit substrates to Cul3 and how their dimerization and conformational variability may facilitate avid interactions with diverse substrates.

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